In the manufacture of one type of insulated wire, bare wire is advanced through a bath of a latex adhesive and then passed through a wiping die which is slightly larger than the diameter of the wire. The latex wire is subsequently passed through apparatus which functions to apply pulp insulation. In other types of wire insulating processes, continuous lengths of wire are advanced through an extruder die which functions to apply a coating of plastic insulating material. In order to provide a continous supply of wire to these apparatuses, wire sections are welded together usually by a coldwelding process.
In a coldwelding process the end section of the exhausted wire is forcibly abutted against the leading end section of a new wire with sufficient force to cold flow and fuse the abutted end surfaces of the respective wires. The wire metal at the weld joint bulges outwardly and may form a circumferential flash about the weld.
The resulting bulbous weldment should be removed prior to advance through a wiping or extruder die. If the weldment bulge is not removed, there is a possibility of either damage to the die or a break in the wire upon impact of the weldment bulge against the inner surface of the die.
If the weldment passes through the die, another detrimental situation may evolve in that the insulation applied to the weldment bulge will be thinner than the insulation on the remainder of the wire. When wires with thin insulation spots are subsequently cabled with other wires, there is a possibility that the weldment bulge will break through the jacketing insulation and through the insulation on one or more adjacent wires to form shorts in the cable.
Heretofore, the usual practice utilized to remove weldment bulges from small diameter wire, e.g., 26-gauge or the like, has been to rub an emery or other abrasive coated cloth or paper back and forth along the wire. However, during the coldwelding operation, the weldment is work hardened or embrittled, thus the rubbing of the emery cloth results in an erosion of the wire on both sides of the weldment. Obviously, these reduced wire sections lead to breaks in the wire during subsequent processing of the wire through various types of equipment, such as wire pair twistors or cabling machines. These breaks result in lost production time, in making repairs and in re-stringing the wire through the processing machine.
Many prior art devices have been developed in an attempt to remove weldment bulges. More particularly, there is shown in the prior patent art, as exemplified by U.S. Pat. No. 2,920,511 issued Jan. 12, 1960 to K. F. Johnson, U.S. Pat. No. 2,945,117 issued July 12, 1960 to Harris et al. and U.S. Pat. No. 3,790,058 issued Feb. 5, 1974 to Filkorn, coldwelding or hotwelding equipment for fusing the end of one wire onto the end of a second wire. These apparatuses also include weldment bulge removal facilities which contemplate movement of one or more conical cutters relative to and along the axes of the joined wires to shear the weldment bulge. These apparatuses are expensive and require maintenance in that the conical tools must be removed and sharpened on a frequent schedule.